Fig 1.
The chronic application of dexamethasone increases GABA release from inhibitory neurons and GABAergic receptor responses in excitatory neurons of the amygdala.
DEX was used by intraperitoneal injections (40 mg/kg) per day for a week. sIPSCs were recorded in the glutamatergic neurons of the brain slices including the amygdala. A) shows sIPSCs in DEX injection (right panel) and saline injection (left). The calibration bars are 7 pA versus 2 seconds (top traces) and 90 ms (bottoms). B) illustrates cumulative probability versus sIPSC amplitudes in DEX injection (red symbols) and saline injection (blue). C) shows cumulative probability versus inter-sIPSC intervals in DEX injection (red symbols) and saline injection (blues).
Fig 2.
The acute application of dexamethasone increases GABA release from inhibitory neurons of the amygdala.
DEX was administrated by washing into the brain slices (25 μM). sIPSCs were recorded in the glutamatergic neurons of brain slices including the amygdala. A) shows sIPSCs in the control (left panel) and DEX-washing (right). Calibration bars are 20 pA versus 2 seconds (top traces) and 90 ms (bottoms). B) shows cumulative probability versus sIPSC amplitude in the control (blue symbols) and DEX-washing (reds). C) illustrates cumulative probability versus inter-sIPSC intervals in the control (blue symbols) and DEX-washing (reds).
Fig 3.
Dexamethasone increases the spike capability of inhibitory neurons in the amygdala.
Sequential spikes were induced by depolarization pulses in the GABAergic neurons of the brain slices including the amygdala. A~B) DEX was used by intraperitoneal injections (40 mg/kg) per day for one week. A) shows sequential spikes in DEX injection (red trace) and saline injection (blue). Calibration bars are 10 mV versus 20 ms. B) illustrates inter-spike intervals versus number of spikes in DEX injection (red bars) and saline injection (blues). An asterisk is p<0.05 and two asterisks are p<0.01. C~D) DEX was administrated by washing into the brain slices (25 μM). C) shows sequential spikes in the control (blue trace) and DEX-washing (red). Calibration bars are 10 mV versus 20 ms. D) illustrates inter-spike intervals versus number of spikes in the control (blue bar) and DEX-washing (red). An asterisk is p<0.05, two asterisks are p<0.01 and three asterisks are p<0.001.
Fig 4.
The chronic application of dexamethasone decreases glutamate release from excitatory neurons and increases glutamate receptor responses in the inhibitory neurons of the amygdala.
DEX was used by intraperitoneal injections (40 mg/kg) per day for a week. sEPSCs were recorded in glutamatergic neurons of the brain slices including the amygdala. A) shows sEPSCs in DEX injection (right panel) and saline injection (left). The calibration bars are 6 pA versus 2 seconds (top traces) and 100 ms (bottom traces). B) shows cumulative probability vs. sEPSC amplitudes in DEX injection (red symbols) and saline injection (blue). C) shows cumulative probability versus inter-sEPSC intervals in DEX injection (red symbols) and saline injection (blue).
Fig 5.
The acute application of dexamethasone decreases glutamate release from excitatory neurons of the amygdala.
DEX was administrated by washing into the brain slices (25 μM). sEPSCs were recorded in the glutamatergic neurons of brain slices including the amygdala. A) shows sEPSCs in the control (left panel) and DEX-washing (right). The calibration bars are 10 pA versus 2 seconds (top traces) and 50 ms (bottoms). B) illustrates cumulative probability versus sEPSC amplitude in the control (blue symbols) and DEX-washing (red). C) illustrates cumulative probability versus inter-sEPSC intervals in the control (blue symbols) and DEX-washing (red).
Fig 6.
Dexamethasone does not affect spike abilities of excitatory neurons in the amygdala.
Sequential spikes were induced by depolarization pulse in the glutamatergic neurons of the brain slices including the amygdala. A~B) DEX was used by intraperitoneal injections (40 mg/kg) per day for one week. A) shows sequential spikes in DEX injection (red trace) and saline injection (blue). Calibration bars are 10 mV vs. 30 ms. B) illustrates inter-spike intervals versus number of spikes in DEX injection (red bars) and saline injection (blues). An asterisk is p<0.05. C~D) DEX was administrated by washing into the brain slices (25 μM). C) shows sequential spikes in the control (blue trace) and DEX-washing (red). Calibration bars are 10 mV and 30 ms. D) illustrates inter-spike intervals versus number of spikes in the control (blue bar) and DEX-washing (red). An asterisk is p<0.05.
Fig 7.
The differential effects of glucocorticoid on inhibitory and excitatory neurons in the basal lateral area (BLA) of the amygdala.
Dexamethasone upregulates the action onto the glutamatergic neurons from GABAergic neurons by elevating presynaptic neuronal excitability, GABA release as well as postsynaptic GABAA receptor responses. Dexamethasone downregulates the action onto the GABAergic neurons from glutamatergic neurons by lowering glutamate release. These alternations imbalance neural networks in the amygdala toward inhibitory state that may be involved in emotional disorders induced by stress hormones.